Wire tying power tool

Abstract

In a power tool for binding concrete-reinforcing bars together with a wire tie, a predetermined length of wire is fed into a pair of jaws having loop-forming grooves therein. A rotatable inner mandrel carries a cutter bar while an outer mandrel is rotatably mounted on the inner mandrel. Radial flanges on the outer mandrel form openings with the cutter bar for the passage of the wire as it is formed into a loop by the jaws. Relative rotation of the inner mandrel relative to the outer mandrel cuts the wire and then twists the cut ends into a wire tie that binds the reinforcing bar. Controls are provided for properly positioning the openings for the passage of the wire upon each successive cycle of operation.

We claim: 
     
       1. A tool for binding with wire reinforcing bars used in concrete structures, said tool comprising: (a) a pair of jaws relatively movable toward and away from each other between open and closed positions for insertion around two or more reinforcing bars,   (b) means for selectively moving said jaws between their open and closed positions,   (c) said jaws having grooves formed therein in the configuration of a loop when the jaws are in their closed position,   (d) means for feeding a predetermined length of wire having a free end into the grooves when the jaws are in their closed position,   (e) wire-retaining means on the jaws for blocking the exit of the wire from the grooves during the feeding of the wire into the grooves in the jaws,   (f) means for cutting the wire after it has been fed all the way into the grooves in the jaws, and   (g) means for twisting the cut ends of the wire to form a tie for binding the reinforcing bars.   
     
     
       2. A tool as set forth in claim 1 wherein the wire-retaining means on one of said jaws is removed from its wire-retaining position as the jaws move from their closed position to an open position. 
     
     
       3. A tool as set forth in claim 2 wherein the wire-retaining means on the other of said jaws is adapted to permit the escape of the wire from the grooves by lateral movement of the wire during the twisting of the cut ends of the wire. 
     
     
       4. A tool as set forth in claim 3 wherein the grooves in the jaws have sections that are substantially straight and sections that are curved and said wire-retaining means are positioned adjacent the transition points between the straight and curved sections of the grooves. 
     
     
       5. A tool as set forth in claim 4 wherein the wire-retaining means on one of said jaws comprises a retractable pin and the wire-retaining means on the other of said jaws comprises a lip covering the terminal portion of the groove in the jaw. 
     
     
       6. A tool as set forth in claim 4 wherein one of said jaws is stationary. 
     
     
       7. A tool as set forth in claim 5 wherein the groove adjacent the lip is cut away to permit lateral movement of the wire out of the groove. 
     
     
       8. A tool for binding with wire reinforcing bars used in concrete structures, said tool comprising: (a) a pair of jaws relatively movable toward and away from each other between open and closed positions for insertion around two or more reinforcing bars,   (b) means for selectively moving said jaws between their open and closed positions,   (c) said jaws having grooves formed therein in the configuration of a loop when the jaws are in the closed position,   (d) a pair of relatively rotatable members forming a pair of openings therebetween,   (e) means for feeding a predetermined length of wire having a free end through one of the openings between said relatively rotatable members, into the grooves in the jaws while the jaws are closed, and the free end of the wire through the other of said openings between the relatively rotatable members,   (f) means for causing one of said relatively rotatable members to rotate relative to said other member to close the openings therebetween, said one member having a cutter thereon to cut the wire and to twist the cut ends of the wire into tie for binding the reinforcing bars upon further rotation of said members.   
     
     
       9. A tool as set forth in claim 8 wherein said relatively rotatable members are rotated to cut and twist the wire as the jaws move from a closed to an open position. 
     
     
       10. A tool as set forth in claim 9 wherein said relatively rotatable members comprise an inner mandrel and an outer mandrel rotatable thereon and said inner mandrel is provided with a cutter bar and said outer mandrel is provided with radial flanges in line with said cutter bar. 
     
     
       11. A tool as set forth in claim 10 wherein means are provided for normally rotating said outer mandrel relative to said inner mandrel so as to provide openings between said cutter bar and radial flanges. 
     
     
       12. A tool as set forth in claim 11 wherein brake means are provided for selectively applying a drag to rotation of the outer mandrel so as to cause the inner mandrel to rotate relative to the outer mandrel and close the openings between the cutter bar and radial flanges. 
     
     
       13. A tool as set forth in claim 12 wherein the tool is provided with means for stopping the inner mandrel at the end of each cycle of operation in the same position it occupied at the start of the cycle. 
     
     
       14. A tool as set forth in claim 13 wherein said means for normally spacing the outer mandrel relative to the inner mandrel operates to provide openings between said cutter bar and said radial flanges after the inner mandrel has been stopped in its original position at the end of the cycle of operation. 
     
     
       15. A tool for binding with wire reinforcing bars used in concrete structures, said tool comprising: (a) a stationary jaw,   (b) a moveable jaw moveable toward and away from said stationary jaw between open and closed positions,   (c) said jaws having grooves formed therein in the configuration of a loop when the jaws are in the closed position,   (d) means for selectively moving said moveable jaw between the open and closed positions,   (e) relatively rotatable members including an inner mandrel and an outer mandrel rotatable thereon,   (f) said inner mandrel having a cutter bar and said outer mandrel having radial flanges in line with the cutter bar,   (g) means for normally rotating said outer mandrel relative to the inner mandrel so as to provide a pair of openings between said cutter bar and radial flanges,   (h) means for feeding a predetermined length of wire having a free end through one of the openings between said inner and outer mandrels into the grooves in jaws while the jaws are in their closed position and the free end of the wire through the other of said openings,   (i) brake means for selectively applying a drag to rotation of the outer mandrel to cause the cutter bar to cut the wire and pinch the wire ends against the radial flanges on the outer mandrel, and   (j) means for automatically opening the jaws and rotating said inner and outer mandrels to twist the ends of the wire into a binding tie.